Solidifier for liquid medical waste

ABSTRACT

A solidifier for liquid medical waste disposed in a vessel, the solidifier comprising a mixture of absorbents having different apparent densities whereby at least one absorbent is negatively buoyant and at least one absorbent is positively buoyant relative to the liquid medical waste. Packaging for the solidifier is disclosed for effecting selective dispersal of the solidifier within the liquid medical waste disposed in the vessel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of copending application Ser.No. 09/865,141, filed May 24, 2001, entitled: SOLIDIFIER FOR A LIQUID,entirety of which is incorporated herein by reference and upon whichpriority is claimed

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

FIELD OF INVENTION

This invention relates to the handling and disposal of flowable (liquid)medical waste, such as body fluids, irrigants, and related flowablematerials. Whereas at times herein, such liquid medical waste isreferred to as a “liquid”, it is to be recognized that when so used, theterm “liquid” is deemed to be synonymous with “liquid medical waste”unless the context in which the term is used clearly indicatesotherwise, and either term is deemed to include any flowable waste whichresults from, is generated in association with, the diagnosis, treatmentor prevention of disease, or bodily injury, including surgicalprocedures, particularly invasive surgical procedures, or othermedically related event which generates liquid (flowable) waste.

BACKGROUND OF INVENTION

Liquid medical waste commonly is collected at the site of its generationin a collection vessel adapted to receive and retain therein the liquidmedical waste. Such wastes may, and often do, include medicallycontaminating organisms, chemical moieties, etc. Such liquid medicalwaste is flowable, much like water. Of necessity, such vessels mustinclude some form of opening or port into the vessel and through whichthe liquid medical waste is introduced into the vessel. Consequently,the vessel is subject to spillage of such collected liquid medical wastedue to outflow of collected waste from the vessel via its entry port,with potential for contamination of the ambient environment and/orpersonnel which might be exposed to the spilled liquid waste In thehandling and disposal of liquid medical waste it has been proposed tointroduce into a vessel containing liquid medical waste, a gel-formingchemical compound which is intended to render the liquid medical wastein the vessel non-flowable. Desirably, the conversion of the flowablewaste to a non-flowable waste is rapid and complete. Commonly, vesselscontaining a collection of liquid medical waste become filled before thecompletion of a medical event, such as surgery, thereby requiringexchange of a filled vessel with a fresh empty vessel. In most otherinstances, upon the completion of the medical event, it is desired thatthe vessel be substantially immediately removed from the operativearena. Either such event affords an opportunity for spillage of flowablemedical waste from the vessel. Hence, rapidity of conversion is neededto permit the conversion to take place before, or immediately after, thecompletion of the event which generates the liquid medical waste andbefore the vessel must be handled or moved and thereby subject toinadvertent spillage. The need for completeness of the conversion isobvious since incomplete conversion will result in the continuedexistence of flowable liquid medical waste being present in the vessel,thereby essentially defeating the purpose of the conversion. As afurther factor, “Solidification” or “stabilization”, as these terms areused herein is intended to refer to the alteration of the state of aflowable medical waste in a collection vessel to a substantiallynon-flowable medical waste without removal of the medical waste fromsuch collection vessel. The agent employed to effect the solidificationor stabilization is at times herein referred to as a “solidifier”.

In the prior art medical applications, single component super-absorbentshave been used for stabilizing liquid infectious waste within acontainer against spillage through inadvertent tipping of the containerin the course of a medical procedure, or during transfer, storage and/ordisposal of the waste.

Known super absorbents heretofore used in the field of liquid medicalwaste may be characterized by a variety of properties. One such propertyis the apparent density (also termed “bulk density”) of the superabsorbent relative to other super absorbents and/or relative to thedensity of the liquid sought to be stabilized. For example, the superabsorbent may either sink or float with respect to the liquid collectedin a vessel and which is intended to be stabilized, i.e. madenon-flowable. For example, an absorbent having a density greater thanthe liquid to be stabilized will “sink” relative to the liquid inquestion and therefore would commence its stabilization action at thebottom of the liquid in the vessel and the stabilization action wouldprogress upwardly through the liquid in the vessel. On the other hand,if the super absorbent is of lesser density than the density of theliquid medical waste in the vessel, the super absorbent will “float” andcommence its stabilization activity at the upper level of the liquid,with the stabilization action progressing downwardly through the liquid.Each of these events is undesirable when working with liquid medicalwaste. In either event, the rapidity of completion of the stabilizationevent is most often insufficient to render the liquid medical wastenon-flowable before the vessel with its collected liquid medical waste,must be handled, thereby substantially negating the usefulness of thesingle component super absorbent. Further, commencement of thestabilization event at one or the other of the top or bottom of thevessel can result in the formation of a graduation of stabilization ofthe liquid medical waste between the top and bottom ends of the vessel,even to the extent that “pockets” of flowable liquid medical waste areformed intermediate the top and bottom of the vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a package containing a mixtureof absorbents disposed in a liquid to be solidified.

FIG. 2 is a schematic diagram of a package containing a mixture ofabsorbents in accordance with one aspect of the present invention; and

SUMMARY OF INVENTION

In accordance with one aspect of the present invention, the presentinventor has discovered a solidifier which comprises a plurality ofcomponents, specifically first and second absorbents having respectivedifferent apparent (bulk) densities, which in combination provide uniquestabilization results with respect to liquid medical wastes disposed ina vessel. In the present invention, the “density” of the absorbent takesinto consideration the bulk density of the absorbent. This, and/or other“density” factors are used to determine whether the absorbent “floats”or “sinks” when introduced into flowable liquid medical waste containedin a vessel. For example, whether a given absorbent, or mixture ofabsorbents, floats or sinks with respect to a liquid may be influencedby factors such as the overall shape of the particles of the absorbent,wetability of the absorbent particle by the liquid medical waste,entrapment of air, etc., as well as the specific gravity of theparticles of the absorbent. Thus, the terms “floaters” and “sinkers”,are used herein, at times, to characterize a given absorbent or mixtureof absorbents (a solidifier), with reference to whether the absorbent ormixture of absorbents, as a whole, starts its activation processpredominantly adjacent the bottom of the vessel or predominatelyadjacent the upper surface of liquid medical waste in the vessel.

In one solidifier of the present invention, there is provided a mixtureof a first absorbent having an apparent bulk density, hence a buoyancy,which is negative relative to the liquid sought to be stabilized, and asecond absorbent having an apparent density, hence a buoyancy which ispositive relative to the liquid medical waste contained in a vessel andsought to be stabilized. Depending upon the desired progression ofsolidification and/or the rate of solidification sought, the mixture ofabsorbents may be selected to provide a very large variety ofsolidification effects within a given liquid medical waste contained ina vessel.

In accordance with another aspect of the present invention, the presentinventor provides controlled dispersion of two or more absorbents withina liquid medical waste contained in a vessel through selection of theselective dispersion of the absorbents by means of the packagingemployed.

DETAILED DESCRIPTION OF INVENTION

Liquid medical wastes commonly exhibit a density equivalent to thedensity of a 0.9% saline solution, such solutions being commonlyemployed in medical events. In accordance with the present inventioneach of the absorbents of the solidifier employed for stabilization ofpreferably is in a powder form. In any event, each of the absorbentswill either be negatively buoyant or positively. buoyant in a 0.9%saline solution, for example, depending upon the apparent (bulk) densityof a given absorbent. Typically an apparent density of the absorbentbelow about 0.5 g/cm³ will result in a positive buoyancy, while anapparent density of the absorbent of about 0.7 g/cm³ will result in anegative buoyancy in a 0.9% saline solution.

For present purposes, examples of the present invention are presentedwith respect to medical liquid wastes as typified by a 0.9% salinesolution at room temperature. Given the parameters set forth herein, oneskilled in the art may readily compound other like effective solidifiersfor other liquid (flowable) medical waste contained in a vessel. In allinstances, however, it is critical to the present invention that therebe a predetermined relationship between the buoyancy of each absorbentemployed relative to the density of the liquid medical waste sought tobe stabilized.

With respect to liquid medical waste applications, several specificabsorbent compounds, all available in powder form, have been identifiedto achieve the desired buoyancy characteristics of the presentsolidifier. For example, in the. positive buoyancy categoryAbsorb-O-Gel™, available from Pioneer Medical, Aqua-Keep™ J550,manufactured by Sumitomo and available from Absorbent Technologies andNorscoryl™ S-35, manufactured by Emerging Technologies, Inc. andavailable through The Chemical Company, each has a bulk density thatresult in positive buoyancy relative to the referent saline solution.Also, in the negative buoyancy category Medigel™ 300, available fromBASF, Flosorb™ 60, available from Chemtall, Inc., and SA60N type II,available from Absorbent Technologies, each has a bulk density whichresults in a negative buoyancy relative to the referent saline solution.

Stated generally, floater absorbents absorb faster (hence solidifyfaster) that do sinkers, but have a lower absorbing capacity relative tosinkers. Also, the rate of solidification is dependent upon the ratio ofthe amount of the absorbent used per given volume of liquid. Stillfurther, the speed and capacity of solidification of a given absorbentvaries according to the type of solution being treated. For example, thesolidification action of sodium-based polyacrylate absorbent in a salinesolution is of lesser capacity than the solidification action of thisabsorbent in tap water, for example.

In accordance with one aspect of the present invention, a combination offloating and sinking powdered absorbents is provided. In one embodiment,the specific mixture includes between about 20% and 80%, by weight, of asinking absorbent and between about 20% and 80%, by weight, of thefloating absorbent. A mixture of absorbents within these stated rangesof weight percentages, provides for relatively uniform and rapidconversion of the referent liquid medical waste in a vessel to a gelwhich is non-flowable. Greater percentages of the sinking absorbentpromotes earlier commencement of solidification of the liquid adjacentthe bottom of the vessel of liquid, relative to the commencement andcompletion of solidification of the flowable liquid medical wasteadjacent the surface of the liquid in the vessel. In similar manner,lesser percentages of the sinking absorbent reverses this commencementof solidification of the liquid medical waste within the vessel.

In the foregoing example of percentages of absorbents, the mixture ofpowdered absorbents is presumed to be introduced into the vessel ofliquid medical waste in the form of a flowing stream of substantiallyuniform volume of the mixture, and that the two absorbents commence andcomplete their solidification activity at substantially the same ratesof solidification. In those instances where it is desired that thesolidification of the liquid commence and attain completion adjacent thebottom of the vessel, in addition to the relative bulk, densities of thetwo absorbents, one need take into consideration the relative rates atwhich the two absorbents effect solidification. Faster-actingabsorbents, either a floater or a sinker, can create undesirable, oreven deleterious effects. For example, even when the mixture is ofsubstantially equal quantities, by weight, of the two absorbents, if thefloater absorbent is faster-acting than the sinker absorbent, thefaster-acting absorbent may form a solid or semi-solid cap at thesurface of the liquid medical waste in the vessel which captures orprecludes the movement: of the sinker absorbent past the cap, therebyresulting in incomplete solidification of the remainder of the liquidwithin the vessel. On the other hand, if the sinker absorbent of thismixture is the faster-acting absorbent, then the solidification of theliquid may proceed “from the bottom up” within the vessel, which can bea desired result, but would not be desired where a minimum time for fullsolidification of the liquid medical waste in the vessel was a criticaldesired result.

In any event, the present combination of absorbents provides a benefitover the use of a single absorbent. More specifically, when using asingle absorbent, solidification can only commence and proceed tocompletion either from the top-down or from the bottom-up within thecontainer. If the single component absorbent is introduced into thevessel at a location partway between the bottom and top level of theliquid medical waste in a vessel, only partial solidification of theliquid medical waste within the vessel would be effected since theabsorbent would either sink or float away from its point of introductioninto the vessel, leaving a portion of the liquid medical wasteunstabilized above or below the introduction point. In either of thesesituations, the initially solidified portion of the liquid medical wastein the vessel tends to capture a portion of the absorbent within thesuch initially solidified portion and delay the migration of theabsorbent to other portions of the liquid. Where time is of the essence,such action is not acceptable, as in liquid medical wastes contained ina vessel. Moreover, where time is not of the essence, single absorbentstend to incompletely disperse throughout the liquid medical waste in thevessel, leaving pockets of flowable liquid medical waste within thevessel—a situation which can be disastrous when handling liquid medicalwaste.

In the mixture of the present invention, the fact that the absorbentworks from both the bottom-up and from the top-down, greatly enhancesthe ability of the absorbent mixture rapidly and fully solidify or gelthe liquid medical waste. This combination of the present invention alsoeliminates the need for stirring of the liquid medical waste to ensuredistribution of the absorbent throughout the liquid medical waste, whichaction can splash liquid from the vessel, or other spillage from thevessel.

The following examples set forth two tests which record the timesconsumed in solidification of 500 cc of tap water at room temperatureemploying different percentage compositions of sinkers and floaters, andprovide guidance to one skilled in the art for formulating furthermixtures, etc.:

Fifteen grams of a powder mixture of Flosorb™ 60 sinker, having anapparent density of about 0.7 and Aqua Keep™ J550 floater, having anapparent density of about 0.4, employing the percentages by weight givenin the following Tables was added via a funnel to a vessel containing500 cc of tap water. The powder mixture was poured through the funnel ata uniform rate of 7 gm/sec, without stirring. No substantial clumping ofthe mixture within the liquid was noted. The predominant portion of theparticles of the Flosorb™ 60 was in the range of 500 to 800 micrometers,and in the range of 100-200 micrometers for the AquaKeep J550. Theobserved times for solidification of the water in the container aregiven in the Table I. TABLE I Time to Sinker Floater Solidify (% by wt)(% by wt.) (sec.) 100 0 150 80 20 90 60 40 30 40 60 28 20 80 38 0 100 40

A further test was conducted identically with the test describedhereinabove except the sinker was BASF 2103 and the floater wasNorscoryl S35 (predominant particle size range of 100-500 micrometers.TABLE II Time to Sinker Floater Solidify (% by wt) (% by wt.) (sec.) 1000 240 80 20 74 60 40 60 40 60 45 20 80 40 0 100 37

In a further test, the sinker of the second test, at 100% by wt.,clumped significantly when added to the water, but when mixed with thefloater, no significant clumping of the mixture was noted. Avoidingclumping of the mixture within the liquid is of major import in thepresent invention, in that clumping prohibits full utilization of thequantity of the mixture and less than complete solidification per unitof absorbent used.

In similar manner, the present inventor has discovered that inclusion ina mixture of a sinker absorbent and a floater absorbent, a thirdabsorbent which also is a sinker, and which may have the same bulkdensity but a particle shape different from the other sinker absorbent,one can achieve more complete and uniform dispersion of the more densesinker. This effect has been found also to be enhanced by choosing athird sinker absorbent which has a larger average particle size thandoes the more dense sinker. In one test, 50% by weight of Aqua-Keep J550(floater) was mixed with 10% by weight of ASAP 2102 (“light sinker”) and40% by weight of Flosorb 60 (“heavy sinker”). This mixture exhibitedenhanced dispersion of the Flosorb 60 absorbent as compared to thedispersion of the Flosorb 60 employed without the second sinkerabsorbent.

In a further embodiment of the present invention, a second sinkerabsorbent was added to the two-absorbent mixture to produce athree-component mixture of absorbents. This added sinker was found toenhance the dispersion of all of the absorbents throughout the volume ofthe liquid, particularly the dispersion of the sinkers. In one example,50% by wt. of Flosorb™ 60 (first sinker), 10% by wt. of BASF 2102(second sinker) and 40% by wt. of Absorb-O-Gel (floater) were mixed todefme a three component absorbent system. This mixture exhibited thedescribed enhancement of dispersion of the several absorbents of themixture, particularly the dispersion of the sinkers. Having thisknowledge, one skilled in the art will recognize that through the choiceof the three components of the mixture, one can obtain substantiallysimultaneous solidification at the bottom, top and central portions ofthe liquid, hence enhanced reduction of solidification time.

It will be recognized by one skilled in the art that the relativepercentages of the absorbents used may be varied to suit particularliquid medical waste concerns. For example, in some types of liquidmedical waste it may be desired for more of the solidification to takeplace from the bottom-up, but it is still desired to have a buoyantabsorbent to form a cap at the top surface of the liquid whilesolidification takes place. In this instance, the relative percentage ofsinker absorbent may be increased and the percentage of floaterabsorbent may be relatively decreased. Such a situation might occur whenthere is primary concern about the loss of liquid medical waste from thebottom of the vessel (as from a discharge port), but the floating capwould also be useful minimizing or precluding spillage or evaporation ofthe liquid medical waste from the top of the vessel. Conversely, therelative percentages may be adjusted in the opposite manner where flowof the liquid, or spillage from a vessel that must be moved, is theprimary concern, but where escape of liquid medical waste from thebottom or the vessel, or simply more rapid solidification, is also aconcern.

In accordance with the basic concept of the present invention one caneither prevent or use to one's advantage the potential stratificationissues that arise due to the use of only a single absorbent which has asingle given buoyancy relative to the liquid medical waste to besolidified. This advantage is accomplished through the use of multipleabsorbents mixed together, preferably in powder form, and introducedinto the body of liquid medical waste in a vessel to be solidified in asubstantially uniform flowing stream of the mixture, such absorbentsbeing chosen on the basis of their buoyancies relative to the liquid tobe solidified.

In accordance with another aspect of the present invention, the mannerof introduction of the mixture of absorbents into the liquid medicalwaste in a vessel has been found by the present inventor to be ofimportance. In this respect, packaging of the powder mixture can beselected to accomplish controlled delivery of selected quantities of agiven absorbent, or a given mixture of absorbents, or both, into theliquid medical waste at a preselected vertical level within the liquidmedical waste contained in a vessel. FIG. 1 depicts one embodiment of anelongated package containing a mixture of absorbent(s). In oneembodiment, the packaging material is of a material which is soluble inthe liquid medical waste which is to be solidified. For example, apackage formed of rice paper or even a light basis weight cellulosicpaper may be employed when dealing with liquid medical wastes. Specificsoluble packaging materials include Acetate Dissolvo and AlcoholDissolvo fabric from CMS Gilbreth Packaging Systems, Inc.

In the embodiment of FIG. 1, the package 20 was filled with a mixture 22of 50% by wt. of Aqua-Keep J550, 10%, by wt. of ASAP 2102 and 40% by wt.of Flosorb 60. The packaging material for the depicted package waspolyvinyl alcohol which readily absorbs in liquid medical wastes. Asdepicted in FIG. 2, upon admission of the package 20 of absorbentmixture into a vessel 24 containing liquid medical waste 26 to besolidified, the package commences dissolving and the contents 22 thereofare released into the liquid medical waste in the vessel 24. Thereupon,the sinkers 28 gravitate to the bottom 30 of the vessel and the floaters32 rise toward the top surface 34 of the liquid medical waste, therebysubstantially distributing the absorbents to their respective desiredlocations within the liquid medical waste. Through the use of anelongated package, there is a greater likelihood that the package willenter the liquid medical waste and lodge within the vessel with one endof the package disposed adjacent the bottom of the vessel and theopposite end of the package being disposed above the bottom of thevessel, thereby enhancing the distribution of the mixture within theliquid medical waste in the vessel and resultant enhanced speed andcompleteness of solidification of the liquid medical waste. Irrespectiveof the ultimate orientation of a package of a mixture of absorbents, theuse of a packaged mixture of absorbents provides enhanced dispersion ofthe absorbents, as compared to pouring of the mixture into a vesselcontaining the liquid medical waste, thereby enhancing the desiredstabilization of the liquid medical waste in the vessel.

Another packaging related embodiment relates to the segregation of thedifferent buoyant absorbents into different packaging compartments of anoverall singular package with the overall packaging made of a materialwhich dissolves or disintegrates when immersed within the liquid medicalwaste. In this embodiment, each absorbent is placed with a differentcompartment in the packaging and each compartment is engineered withdifferent decomposition or dissolving effects. For example, if thecombination is of floating and sinking absorbents and the desire is torelease the sinker first, so that it does not become trapped by thefloater, the packaging would be engineered so that the compartmentcontaining the sinker would dissolve or disintegrate first, thusreleasing the sinker first. This type of packaging engineering mayutilize a thicker wall-thickness of the dissolving or disintegratingpackaging for containing the floater so that this component would bereleased last., or may utilize different packaging materials ofdifferent rates of dissolution or disintegration. One skilled in the artwill readily recognize similar packaging concepts as well as a mixtureof absorbents in one or both of the different compartments of thepackage. For example, one might choose to employ inner and outerpackages, the outer packages containing the first-to-be releasedabsorbent and the inner package containing the second-to-be releasedabsorbent, etc.

Additionally, the buoyancy of the package itself may be engineered toachieve further solidification effects. For example, the completepackage may be designed to be negatively buoyant so, that the packagewould sink to the bottom of a vessel containing the liquid medicalwaste. There, the package would dissolve, releasing the sinker absorbentand allowing the floater absorbent to rise within the liquid medicalwaste. The converse, that is, designing the package to be positivelybuoyant, would result in release of both the floater and sinkerabsorbents, the floater absorbent being adjacent the top surface of theliquid while the sinker sank toward the bottom of the liquid.

Staged release packaging may also be employed, wherein a portion of amixture of absorbents is released over time, such as in the course ofsinking of the overall package toward the bottom of the vessel whichcontains the liquid.

The foregoing description of various embodiments is provided forpurposes of illustration and not limitation. One skilled in the art willrecognize numerous changes, additions, substitutions or deletions to thefeatures and components described herein. For example, while specificabsorbents have been listed and/or described, a variety of otherabsorbents may be substituted or included in a mixture of absorbents fora given set of circumstances involving solidification of a liquid or amixture of liquids, etc., without departing from the scope of thepresent invention.

1. a solidifier for the solidification of a volume of liquid medicalwaste contained in a vessel comprising: a first absorbent, a secondabsorbent, said first absorbent having an apparent density which renderssaid first absorbent positively buoyant relative to the liquid medicalwaste disposed within the vessel, said second absorbent having anapparent density which renders said second absorbent negatively buoyantrelative to the liquid medical waste disposed within the vessel.
 2. Thesolidified of claim 1 wherein said first and second absorbents comprisea mixture thereof.
 3. The solidifier of claim 2 wherein said mixturecomprises substantially equal parts, by weight, of said first and secondabsorbents.
 4. The solidifier of claim 1 wherein said mixture comprisesgreater that fifty percent, by weight, of said second absorbent wherebysaid second absorbent gravitates toward the bottom of said vessel. 5.The solidifier of claim 1 wherein said first absorbent comprises betweenabout eighty percent and about twenty percent, by weight of said firstabsorbent.
 6. The solidifier of claim 1 and including a third absorbent.7. The solidifier of claim 6 wherein said third absorbent exhibits anapparent density which renders said third absorbent positively buoyantrelative to the liquid medical waste.
 8. The solidifier of claim 6wherein the apparent density of said third absorbent is intermediate theapparent densities of said first and second absorbents.
 9. Thesolidifier of claim 6 wherein said absorbents comprise a mixture of saidfirst, second and third absorbents.
 10. The solidifier of claim 9wherein said mixture comprises about fifty percent, by weight, of saidsecond absorbent, about ten percent, by weight, of said third absorbent,and about forty percent, by weight, of said first absorbent.
 11. Thesolidifier of claim 6 wherein the average particle size of said thirdabsorbent is greater than the average particle size of said secondabsorbent.
 12. The solidifier of claim 1 wherein each of said absorbentsis in the form of a flowable powder.
 13. The solidifier of claim 1 andfurther including packaging for said mixture which is dissolvable ordisintegrative when disposed in the liquid medical waste.
 14. Thesolidifier of claim 13 wherein said packaging comprises two or morecompartments, each compartment containing a portion of one or more ofsaid absorbents.
 15. The solidifier of claim 14 wherein said two or morecompartments exhibit different rates of dissolution or disintegrationwhen disposed in the liquid medical waste.
 16. The solidifier of claim 6wherein each of said absorbents is in the form of a flowable powder. 17.The solidifier of claim 6 and further including packaging for saidmixture which is dissolvable or disintegrative when disposed in theliquid medical waste.
 18. The solidifier of claim 17 wherein saidpackaging comprises two or more compartments, each compartmentcontaining a portion of one or more of said absorbents.
 19. Thesolidifier of claim 18 wherein said two or more compartments exhibitdifferent rates of dissolution or disintegration when disposed in saidliquid to be solidified.
 20. A solidifier in powder form for solidifyinga volume of liquid medical waste in a vessel comprising: a first mixtureof powdered absorbents, a second mixture of powdered absorbents, saidfirst mixture of powdered absorbents exhibiting an apparent densitywhich renders said first mixture of powdered absorbents positivelybuoyant relative to the liquid medical waste, said second mixture ofpowdered absorbents exhibiting an apparent density which renders saidsecond mixture of powdered absorbents negatively buoyant relative to theliquid medical waste.
 21. A solidifier for a liquid medical wastedisposed in a vessel and having a density approximating the density of a0.9% saline solution comprising a mixture of a plurality of differentabsorbents, at least one of said absorbents having an apparent densitywhich renders it negatively buoyant in the liquid medical waste, and atleast one of said absorbents having an apparent density which renders itpositively buoyant relative to the liquid medical waste.
 22. Thesolidifier of claim 21 and including packaging for said mixture, saidpackaging being dissolvable or disintegrative when disposed within theliquid medical waste.
 23. The solidifier of claim 21 wherein saidmixture includes at least three different absorbents, two of saidabsorbents having respective apparent densities which render eachnegatively buoyant relative to the liquid medical waste, and the thirdof said absorbents having an apparent density which renders said thirdabsorbent positively buoyant relative to the liquid medical waste. 24.The solidifier of claim 21 wherein said negatively buoyant absorbentsexhibit different apparent densities whereby one of said negativelybuoyant absorbents is more buoyant than the other of said negativelybuoyant absorbents and said absorbent of lesser buoyancy enhances thedistribution within said liquid of said absorbent of greater buoyancy.25. A method for the solidification of a liquid medical waste comprisingthe steps of: introducing the liquid medical waste into a vessel, mixingtogether a first absorbent having an apparent density which renders saidfirst absorbent positively buoyant relative to the liquid medical wastewhereby said first absorbent floats adjacent the surface of the liquid,and at least one further absorbent having an apparent density whichrenders said further absorbent negatively buoyant relative to the liquidmedical waste, whereby said at least one further absorbent sinks towardthe bottom of the liquid medical waste, and introducing at least aportion of said mixture into the liquid medical waste disposed in thevessel.
 26. The method of claim 25 and including the step of mixing astill further absorbent with said first and further absorbents, saidstill further absorbent having an apparent density intermediate thedensities of said first and further absorbents and which renders saidstill further absorbent negatively buoyant relative to the liquidmedical waste disposed within the vessel.
 27. The method of claim 26wherein said still further absorbent exhibits an average particle sizegreater than the average particle size of said at least one furtherabsorbent.